Deciphering the Pharmacological Properties of Methanol Extract of Psychotria calocarpa Leaves by In Vivo, In Vitro and In Silico Approaches

The present study explores the neuropharmacological, antinociceptive, antidiarrheal, antioxidant, thrombolytic and cytotoxic activity of methanol extract of Psychotria calocarpa leaves (MEPC). In anxiolytic activity testing of MEPC by elevated plus maze test, hole-board test and light-dark test, the extract exhibited a dose-dependent reduction of anxiety while the open field test observed a decreased locomotion. The administration of MEPC revealed a significant dose-dependent reduction of depressant behavior in forced swimming and tail suspension test. Additionally, the antinociceptive and antidiarrheal activity exposed a significant reduction of nociception and diarrheal behavior at the highest dose. In addition, a strong antioxidant activity was observed in DPPH-free radical-scavenging assay (IC₅₀ = 461.05 μg/mL), total phenol content (118.31 ± 1.12 mg) and total flavonoid content (100.85 ± 0.97 mg). The significant clot-lysis activity was also observed with moderate toxicity (LC₅₀ = 247.92 μg/mL) level in the lethality assay of brine shrimp. Moreover, in silico molecular docking study showed that the compound Psychotriasine could offer promising active site interactions for binding proteins. Furthermore, ADME/T and toxicological properties of the compound satisfied the Lipinski's rule of five and Veber rules for drug-like potential and toxicity level. Overall, MEPC had a potential neuropharmacological, antinociceptive, antidiarrheal and antioxidant activity that warranted further investigation.

Keywords: Psychotria calocarpa; Rubiaceae; antidepressant; antidiarrheal; antinociceptive; antioxidant; methanol extract; molecular docking.